The long-term objective of this research proposal is to fully characterize the role of Proxl in embryonic and adult lymphangiogenesis. Our laboratory has previously shown that Proxl is critical for the development of the lymphatic vasculature and that Proxl heterozygous mice exhibit a mispatterned and dysfunctional lymphatic system. Furthermore, the fact that Proxl is also expressed in adult mouse lymphatic vessels suggested a likely functional role of Proxl in adult stage lymphagiogenesis in instances of wound healing and inflammation. My research project will strive to fully characterize the lymphatic defects seen in Proxl heterozygous mice using both standard knockout and inducible knockout mouse strains. A combination of cellular and molecular approaches will be used to explore the role of Proxl in both embryonic and adult lymphangiogenesis and to identify the different sources of lymphatic endothelial cell precursors. Taken together, these findings will further advance our knowledge of the developing lymphatic system. [unreadable] [unreadable] [unreadable]